[asterisk-users] G.729 & Voicemail

[Robert Lister]

On Fri, Apr 20, 2007 at 02:59:28PM +0200, Michael Landin Hostbaek wrote:
> List, 
> 
> I have some cisco phones (7940) and asterisk 1.4 running nicely.. Communication
> between the phones is G.729, and my sip.conf looks like this:
> 
> disallow=all                    ; First disallow all codecs
> allow=g729                      ; 
> allow=gsm
> allow=ulaw
> allow=alaw
> 
> However, I cannot call voicemail - I get the following error:
> [Apr 20 14:58:31] WARNING[87184]: channel.c:2816 set_format: Unable to
> find a codec translation path from g729 to gsm
> 
> Shouldn't it switch to gsm automatically?

Cisco 79XX phones only support ulaw, alaw or g729, not gsm.

Asterisk only supports g.729 protocol in passthrough mode without the 
licence (i.e. It can set up a session between two licenced g.729 endpoints 
to talk to each other, but cannot get into the media path itself.)

The voicemail system is presumably trying to transcode from g.729 to gsm and 
you haven't got the licence for that. (Maybe you can get hold of/convert the 
sounds in the g729 format for the voicemail system, then it may not have to 
transcode out of .gsm?) I am not sure what parts of the system are 
enabled/disabled without the licence.

http://www.voip-info.org/wiki-Asterisk+G.729+Licensing

> I cannot purchase g729 licenses, as FreeBSD is not yet supported (with
> asterisk 1.4)